For example, some analysis devices such as chromatographs are provided with a light detection unit including a plurality of light receiving elements, and measurement intensity is input to a control device at a predetermined cycle based on the received amount of measurement light at these light receiving elements. The control device is configured from a computer, for example, and is capable of acquiring, as measurement data, the relationship between the measurement intensity that is input at a predetermined cycle and the measurement time and of processing the measurement data.
With this type of analysis device, a change over time may occur in the measurement intensity because it takes time for the detection sensitivity to stabilize after the analysis is started, for example. Accordingly, some analysis devices adopt a configuration for performing, as an example of processing on the measurement data, calculation of the rate of change (drift) over time in the measurement intensity based on measurement data obtained by background measurement, and a process of correcting the measurement data based on the calculated drift (for example, see Patent Document 1).
FIGS. 3(a) and 3(b) are diagrams for describing conventional modes of calculation of a drift. In FIGS. 3(a) and 3(b), the relationship between the absorbance, which is an example of the measurement intensity, and the measurement time is partially shown as the measurement data.
In the example in FIG. 3(a), by determining a line L1 that is approximate to measurement data by using the least squares method, the slope of the line L1 is calculated as a drift D1. On the other hand, in the example in FIG. 3(b), arbitrary two points P1 and P2 are selected from measurement data and a line L2 that connects these two points P1 and P2 is determined to thereby calculate the slope of the line L2 as a drift D2.